<template>
	<div>
		<router-link 
		  tag="div" 
		  to="/" 
		  class="header-abs"
		  v-show="showAbs"
		>
			<div class="iconfont header-abs-back">&#xe624;</div>
		</router-link>
		<div 
		  class="header-fixed" 
		  v-show="!showAbs"
		  :style="opacityStyle"
		>
			<router-link to="/">
		  	  <div class="iconfont header-fixed-back">&#xe624;</div>
			</router-link>
			景点详情
		</div>
	</div>
</template>

<script>
export default {
	name:'DetailHeader',
	data () {
		return {
			showAbs: true,
			opacityStyle: {
				color: 0
			}
		}
	},
	methods: {
		handleScroll () {
			const top = document.documentElement.scrollTop
			if (top > 60) {
				let opacity = top / 140
				opacity = opacity > 1 ? 1 : opacity
				this.opacityStyle = {
					opacity
				}
				this.showAbs = false
			} else {
				this.showAbs = true
			}
		}
	},
	activated () {
		window.addEventListener('scroll',this.handleScroll)
	},
	deactivated () {
		window.removeEventListener('scroll',this.handleScroll)
	}
}
</script>

<style lang="stylus" scoped>
	@import '~styles/varibles.styl'
	.header-abs
		position: absolute
		left: .2rem
		top: .2rem
		width: .8rem
		height: .8rem
		line-height: .8rem
		text-align: center
		border-radius: .4rem
		background: rgba(0,0,0,.8)
		.header-abs-back
			color: #fff
			font-size: .4rem
	.header-fixed
		z-index: 2
		position:fixed
		top: 0
		left: 0
		right: 0
		overflow:hidden
		height:$headerHeight
		line-height:$headerHeight
		text-align:center
		color:#fff
		background:$bgColor
		font-size: .32rem
		.header-fixed-back
			position:absolute
			top:0
			left:0
			width: .64rem
			text-align: center
			font-size: .4rem
			color:#fff
</style>